The present invention relates to a method of producing a fluid from an earth formation containing separate fluid zones extending at a distance from each other. Economic exploitation of fluid, for example oil or gas, from certain subsurface fluid zones can be economically prohibited due to unacceptably high development costs when conventional exploitation methods are applied. Such a situation can exist in the case of a relatively small offshore hydrocarbon reservoir, the development of which would require facilities such as subsea installations, an offshore platform, umbilicals and pipelines if conventional exploitation methods are applied. It is therefore desirable to provide a method of exploiting such fluid zones in an economically attractive manner.
U.S. Pat. No. 2,736,381 discloses a method of producing a fluid via a production wellbore formed in an earth formation, the earth formation comprising a first fluid zone and a second fluid zone extending at a distance from the first fluid zone, whereby a barrier zone vertically separates said fluid zones from each other. A vertical auxiliary wellbore passes through the barrier zone and extends into the two fluid zones so as to provide fluid communication between the fluid zones. The auxiliary wellbore is closed at its upper end, and fluid is produced which flows from the second fluid zone via the auxiliary wellbore into the first fluid zone and through the production wellbore. The second fluid zone is located below the first fluid zone, and the auxiliary wellbore extends vertically through both fluid zones so that the known method is not suitable to exploit separate fluid zones extending at a horizontal distance from each other.
It is an object of the invention to provide a method of economically producing a fluid from different fluid zones extending at a horizontal distance from each other.